class Shape{

    public void draw(){
        System.out.println("画图形");
    }
}

class Rect extends Shape{

    @Override
    public void draw() {
        System.out.println("画一个矩形");
    }
}

class Cycle extends Shape{
    @Override
    public void draw() {
        System.out.println("画一个圆圈");
    }
}

class Triangle extends Shape{
    @Override
    public void draw() {
        System.out.println("画一个三角形");
    }
}

public class test2 {

    public static void drawMap(Shape shape){
        shape.draw();
    }

    public static void main(String[] args) {
        drawMap(new Cycle());
        drawMap(new Rect());
        drawMap(new Triangle());
    }

}
